key: cord-0797670-lkpvijui
authors: Hsieh, S.-M.; Chang, S.-c.; Cheng, H.-Y.; Shih, S.-R.; Lien, C. E.
title: The reactogenicity and immunogenicity of a booster dose after the second dose of a protein subunit vaccine MVC-COV1901.
date: 2021-12-05
journal: nan
DOI: 10.1101/2021.12.01.21267115
sha: e7e2b1ce89329f77590781e4cae2277e509c47e9
doc_id: 797670
cord_uid: lkpvijui

Abstract: In this extension of the phase 1 clinical study, we report the immunogenicity and reactogenicity of the booster dose of a COVID-19 vaccine, MVC-COV1901, administered six months after the completion of the primary two dose schedule. Antibody persistence was detected at 6 months after the second dose of MVC-COV1901, albeit at reduced levels. At 28 days after the booster dose, the neutralizing antibody titer was 1.7-fold higher compared to the previous peak at 2 weeks after the second dose. These data demonstrated the safety and immunogenicity of booster shot of MVC-COV1901 after the primary schedule of the vaccine.

months after the completion of the primary two dose schedule. Antibody persistence was detected at 6 months after the second dose of MVC-COV1901, albeit at reduced levels. At 28 days after the booster dose, the neutralizing antibody titer was 1.7-fold higher compared to the previous peak at 2 weeks after the second dose. These data demonstrated the safety and immunogenicity of booster shot of MVC-COV1901 after the primary schedule of the vaccine.

Introduction: MVC-COV1901 is a protein subunit COVID-19 vaccine based on the stable prefusion spike protein S-2P adjuvanted with CpG 1018 and aluminum hydroxide. Interim results of phase 2 clinical trial demonstrated favorable reactogenicity and immunogenicity and the vaccine has been authorized for use in Taiwan since August 2021 [1] . However, the antibody persistence after the second dose and the effects of a booster dose remained unknown at the time.

We describe the antibody durability until 180 days after the second dose. Also, we report reactogenicity and the immunogenicity of the booster shot of MVC-COV1901 administered to 45 healthy adults from 20 to 49 years of age on day 209 in an extended Phase 1 study.

Three different dose levels employed in the original Phase 1 trial were low dose (LD), middle dose (MD), and high dose (HD) (5 mcg, 15 mcg, and 25 mcg, respectively) of S-2P protein adjuvanted with CpG 1018 and aluminum hydroxide [2] . MD was used as the booster dose for the LD and MD group, while HD was used for the HD group. Antibody level was measured on day 209 by enzyme-linked immunosorbent assay (ELISA) against SARS-CoV-2 spike protein, and by live-virus SARS-CoV-2 neutralization assay [1] , with NT 50 GMTs expressed as neutralization titer.

. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. for all participants was comparable to that after the previous doses (Appendix C).

vaccines, neutralizing antibody titers have been reported to be highly correlated with vaccine efficacy [3] . Based on Khoury's modelling, a level of neutralizing NT 50 54 IU/mL could render 50% of vaccine efficacy against the prototype strain, which meets the WHO target product profile for COVID-19 vaccine approval. The trough, at 6 months after the primary two doses of MVC-COV1901, of neutralizing NT 50 for MD group was 79.4 IU/mL, which still exceed the above cut-off. The dynamics of antibody titer after the second dose is similar to that of other vaccines, namely increasing to peak at 2 weeks after the administration and decline afterwards but remain detectable on day 209 [4] . The GMT of neutralizing antibody titers of MD showed a 6.2 fold-reduction (495.9/79.4) at 180 days -which is comparable to other platforms [5, 6 ]compared to the peak at 14 days after the second dose. At 28 days after the booster dose, a foldincrease of 1.7 (818.3/495.9) was noted compared to the previous peak. The results showed that antibody response against SARS-CoV-2 can be boosted by the third dose. The data supports the use of the vaccine in further clinical development that involves a 3 rd dose boost. Ongoing monitoring is planned and will give insights to antibody persistence after the third dose.

. CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted December 5, 2021. ; Figure A) anti-SARS-CoV-2 IgG antibody titer expressed in binding antibody titers (BAU/mL) and

Safety and immunogenicity of CpG 1018 and aluminium hydroxideadjuvanted SARS-CoV-2 S-2P protein vaccine MVC-COV1901: interim results of a largescale, double-blind, randomised, placebo-controlled phase 2 trial in Taiwan. The Lancet Respiratory Medicine

Safety and Immunogenicity of a Recombinant Stabilized Prefusion SARS-CoV-2 Spike Protein Vaccine (MVC-COV1901) Adjuvanted With CpG 1018 and Aluminum Hydroxide in Healthy Adults: A Phase 1, Dose-Escalation Study

Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection. Nature medicine

Prospects for durable immune control of SARS-CoV-2 and prevention of reinfection

Antibody persistence through 6 months after the second dose of mRNA-1273 vaccine for Covid-19

Decline of antibody titers 3 months after two doses of BNT162b2 in non-immunocompromised adults. Clinical Microbiology and Infection